CJC-1295 vs Sermorelin.

CJC-1295 vs Sermorelin: What to Know in 2024

Sermorelin and peptide CJC-1295 are both growth hormone-releasing hormone (GHRH) derivatives and thus their properties and functions are often compared to one another. Though they share a number of similar actions, CJC-1295 and sermorelin have distinct differences as well. Which peptide is the “best” choice for a given application depends more upon these peptides’ differences than their similarities.

Sermorelin vs. CJC-1295 Structure

Below are the structures of sermorelin and CJC-1295 laid out in various formats. Notice that sermorelin is simply GHRH 1-29. That is to say, sermorelin is simply the first 29 amino acids from the much larger growth hormone-releasing hormone. CJC-1295 is also made up of the first 29 amino acids of GHRH, but some of the amino acids have been modified.

Sermorelin Structure

Sequence: Tyr-Ala-Asp-Ala-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Val-Leu-Gly-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Met-Ser-Arg

Molecular Formula: C149H246N44O42S

Molecular Weight: 3357.933 g/mol

PubChem CID: 16129620

Source: PubChem

CJC-1295 Structure

Sequence: Tyr-D-Ala-Asp-Ala-Ile-Phe-Thr-Gln-Ser-Tyr-Arg-Lys-Val-Leu-Ala-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Leu-Ser-Arg

Molecular Formula: C152H252N44O42

Molecular Weight: 3367.954 g/mol

PubChem CID: 56841945

Source: PubChem

Sermorelin Amino Acid Sequence:

Tyr-Ala-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Val-Leu-Gly-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Met-Ser-Arg

CJC-1295 Amino Acid Sequence:

Tyr-D-Ala-Asp-Ala-Ile-Phe-Thr-Gln-Ser-Tyr-Arg-Lys-Val-Leu-Ala-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Leu-Ser-Arg

Sermorelin is also referred to as GRF (1-29) which stands for growth hormone releasing factor (1-29). CJC-1295 is a modified form of GRF (1-29) sometimes called mod GRF (1-29) or tetrasubstituted GRF (1-29). The first 29 amino acids of GHRH are as potent as the full 44 amino acids of GHRH, but they tend to be cleared very rapidly via the body’s natural metabolic clearance processes. To reduce the rate of clearance and thus boost half-life, modifications were made to sermorelin to make CJC-1295 more resistant to enzymatic cleavage. Research suggests that the half-life of sermorelin is somewhere on the order of five minutes while the half-life of CJC-1295 is at 30 minutes[1], [2].

The CJC-1295 DAC Argument

Before discussing CJC-1295 and sermorelin any more, it is important to put a long-standing debate to rest, at least for the purposes of this article. CJC-1295 is often modified by the addition of a lysine residue and a chemical structure called DAC to the carboxyterminal end. DAC stands for drug affinity complex. DAC is commonly attached to molecules to help bind them to the blood protein albumin. This helps to extend the half-life of these compounds and extend their duration of action. For CJC-1295, DAC can increase the time to total clearance of CJC-1295 from roughly 60 minutes to more than 96 hours.

There is some debate, even among scientists in the field as to whether the term CJC-1295 applies only to mod GRF (1-29) with DAC added or whether one must specify the “DAC” component because CJC-1295 and mod GRF(1-29) can be used interchangeably. The original developer considered CJC-1295 to be inclusive of DAC. In other words, when someone said “CJC-2195” they meant mod GRF (1-29) with DAC added. Most people specify CJC-1295 with DAC simply to be clear. In this article, CJC-1295 will refer to the DAC modified version of mod GRF (1-29).

Plasma Growth Hormone: Sermorelin vs CJC-1295

Both sermorelin and CJC-1295 raise levels of GH in blood by stimulating the growth hormone releasing hormone receptor in the anterior pituitary gland. Because they both operate at the level of the GHRH receptor, sermorelin and CJC-1295 preserve the normal pulsatile function of GH secretion. Of the two, however, sermorelin provides the more natural ebb and flow of GH because it is cleared from the body faster than CJC-1295[3]. The best way to think of these two peptides and their effects on the GH curve are that while they both raise overall GH levels while relative preserving peaks and troughs, CJC-1295 extends the overall amount of time spent at higher GH levels. In other words, CJC-1295 turns the sharp peaks into plateaus to some extent. This boosts the effects of GH substantially, but it also alters the physiology to some degree. Sermorelin provides the most natural ebb and flow pattern, which is one reason that it is often preferred over peptide CJC-1295.

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